How to construct a mixed effects model for nonlinear simultaneous equations

[sbxkoenk]

Just a title without text in the body of the message isn't really enough to give proper advice.

But are you doing Joint Modeling of Different Types of Responses? 

Like in many biomedical studies one jointly collects longitudinal continuous, binary, and survival outcomes, possibly with some observations missing.

In that case, the SAS procedure NLMIXED is the way to go.

BR, Koen